Electric-arc lamp



UNITED STATES PATENT OEEicE.

JOHN A. MOSHER AND WVILLIAM S. BARTI-IOLOMEXV, OF CHICAGO, ILLINOIS.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 565,861, dated August11, 1896.

Application filed September 23, 1895. Serial No. 56 3,3 18. (N model.)

7 WILLIAM S. BARTHOLOMEW, citizens of the being warping in baking.

United States, and residents of Chicago, county of Cook, and State ofIllinois, have invented certain new and useful Improvements in ElectricArc Lamps, of which the following is a specification,and which is fullyillustrated in the accompanying drawings.

This invention relates to the construction of the frame of the lamp andmore particularly' to the manner of holding and guiding the carbons. Itspurpose is to provide a loose or jointed attachment of the carbons whileinsuring a perfect contact at their points.

The invention is carried into effect by providin g a universal joint forthe carbon-holders and guide-plates for their tips, so that while thebuttv of the carbon is free to move laterally its tip is limited to alongitudinal movement.

NVhile the invention is applicable to any lamp having a localized arc,it is of especial value in connection with the lamp forming the subjectof Letters Patent No. 544,066, issued to J ohn A. lWIosher August 6,1895, in which the arc is formed and maintained between points of thecarbon electrodes in actual and continual contact.

It is found in practice that the carbon pencils are not uniform inshape, a common fault It is important that the electrodes shouldapproach each other directly, and hence that any irregularities in theform of the pencils be compensated for by adjustment at their butts, asa warped or otherwise distorted carbon is apt to bind in the guide-plateintended to bring its tip into proper position unless free to move atits butt.

The difficulties referred to are entirely overcome in the lamphereinafter described and illustrated in the accompanying drawings, inwhich Figure 1 is an elevation of the lamp-frame. Fig. 2 is a plan viewof the upper carbonholder. Fig. 3 is a sectional view on the line 3 3 ofFig. 2. Fig. 4 is a plan view of the lower carbon-holder. Fig. 5 is asectional view on the line 5 5 of Fig. 4:. Figs. 6 and 7 are plansections on the lines 6 6 and '7 7, respectively, of Fig. l; and Fig. 8is a plan view of the cross-plate at the bottom of the frame.

The two main members of the frame, commonly called the posts, are shownatA A, and are pendent from a top plate B and tied together near theirlower ends by a cross-bar a, apertured for the passage therethrough ofthe upper carbon.

A pair of guide-rods O 0, parallel with the posts A A and between thelatter, are secured to the top plate B and cross-bar a, and areinsulated from both of these parts.

A traveling block D runs upon the guiderods 0 O and constitutes theupper carbonholder in the preferred form of construction, having acentral vertical aperture 6 for the reception of the carbon pencil E, alateral way extending from the aperture c, a clamping-block F, locatedwithin the way, and a thumb-screw f, extending from the side of theblock D and bearing against the clampingblock to force it against thecarbon.

The block D is so mounted upon the rods O O as to prevent it from havingany lateral motion and yet allow it to freely tilt. This is accomplishedby giving it a knife-edge hearing upon the rods, formed as shown, byfirst drilling the block to form apertures cl for the rods O O, andwithin which they will make a close fit, and then counter-boring theseapertures from each end almost half through the block, leaving only anarrow annular rib d tapering to an edge and having bearing contact withthe guide-rods.

The aperture in the cross-bar ais sufficiently large to allow the carbonto pass without contact. A guide-plateG is secured to and elec tricallyinsulated from the cross-bar a, and has an aperture through which thecarbon may pass, but without lateral play. The are is locatedimmediately below thecross-bar a.

The posts A A are prolonged a little beyond the location of the arc andtheir lower ends are turned inwardly,as shown,and united by aguide-plate g, for the lower carbon.

Pendent from the inturned ends of the posts A A are a pair of parallelrods J J, upon which runs a traveling cross-head L, carrying the lowercarbon-holder. This carbon-holder is a block M, apertured for thepassage therethrough of the carbon and having a lateral extension Mwithin which is carried a clamping-block m, which may be forced againstthe carbon pencil by a thumb-screw in.

The traveler L is apertured, the sides of the aperture being beveledfrom above. The bottom of the block M is rounded to adapt it to theaperture of the traveler, and from this rounded bottom depend twooppositely-disposed lugs O O, which, after passing through the apertureof the traveler are turned back sufficiently to lock the block andtraveler together, yet not enough to prevent the free play of the block.

I11 the lamp described in the patent referred to the carbons become andremain pointed. The con tact-points become highly heated and fusedtogether, forming a neck. Any lateral displacement of one of theelectrodes would destroy the integrity of this neck and greatly impairthe efficiency of the lamp. Should the carbons not be perfectlystraight, it is obvious that their tips will get out of true alinementunless the irregularity of form is in some way compensated for. The useof a guide-plate near the arc is impracticable without a looseattachment at the holder, as a warped pencil will necessarily bin d inthe guide-plate unless its butt can move sufficiently to compensate forthe irregularity in its shape. Sufficient lateral play at the butt ofthe carbon is provided in the construction shown, while the movement isso much farther from the guide plate than is the are that it does notperceptibly change the position of the contact-point.

In order to shorten the frame as much as possible, provision is made fortrimming the lamp by passing both carbons up from below the tie-plate Kat the bottom of the rods J J having an aperture is of sufficient sizeto receive the carbons, so that in trimming the upper carbon is insertedthrough this plate and passed up through the lower carbonholder and theguide-plates to its proper position, the lower carbon then beingintroduced in the same Way.

The current is brought to the portion of the frame of the lamp hereindescribed by the wires S T, one of which, as S, is insulated from theframe and connected with the traveler D by means of the plate 92,attached to the, top plate 13, the wires 8 s and the bindingscrews 3 sset in the traveler. The other wire, as T, is electrically connectedwith the frame, and the current reaches the lower carbon H, eitherthrough the frame itself or through the Wires if, employed to insure agood circuit leading from the posts A A to binding-screws t If set inthe block M. A rod P is fixed in an extension of the traveler L andextends upwardly through and slides in apertures in the bent end of oneof the posts A and in the cross-bar a. A cord or chain 1) leads from theupper end of the rod P over a pair of sheaves q, suitably jonrna-ledabove the plate 13 and down to the traveler D. The carbon feed isaccomplished by gravity, the traveler D being made heavier than thetraveler L, so that as the carbons are consumed the former falls and thelatter is elevated.

\Ve claim 1. In an arc-lamp, the combination with a frame havingvertical guide-rods, of a carbonholder adapted to slide upon theguide-rods and having a knife-edge bearing thereupon, substantially asdescribed and for the purpose specified.

2. In an arc-lamp, the combination with a frame having guide-rods, of anapertured cross-head adapted to reciprocate upon the rods, the walls ofits aperture being beveled from above, a carbon-holder adapted to restwithin the aperture of the cross-head, an d retaining lugs or clawsprojecting from the holder through the cross-head aperture and beingspread to loosely engage the cross-head, substantially as described andfor the purpose specified.

In an arc-lamp, the combination with a frame having upright members orposts and with upper and lower carbon-holders, of a cross -head forcarrying the lower carbonholder and a tie-plate for uniting the lowerends of the upright members of the frame, such cross-head and tie-platebeing apertured for the passage therethrough of the carbon pencils,substantially as described and for the purpose specified.

4:. In an arc-lamp, the combination with the frame having uprightmembers or posts, and with guide-plates secured to the frame forpreventing angular movement of the tips of the carbon pencils, oftraveling carbon-holders, and a tie-plate forming the bottom of theframe, such tie-plate and the lower carbonholder being verticallyapertured to admit of the introduction of the carbons therethrough intrimming, substantially as described and for the purpose specified.

In testimony whereof we aflix our signatures in presence of twowitnesses.

JOHN A. HOSIIER. XVILLIAM S. BARTIIOLOME\V. lVitnesses:

Louis K. GILLSON, MILO B. GILLsON.

ICC

